SEM/EDX

Technique: Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) is the best known and most widely-used of the surface analytical techniques. High resolution images of surface topography, with excellent depth of field, are produced using a highly-focused, scanning (primary) electron beam. The primary electrons enter a surface with an energy of 0.5 – 30 kV and generate many low energy secondary electrons. The intensity of these secondary electrons is largely governed by the surface topography of the sample. An image of the sample surface can thus be constructed by measuring secondary electron intensity as a function of the position of the scanning primary electron beam. High spatial resolution is possible because the primary electron beam can be focused to a very small spot (<10 nm). High sensitivity to topographic features on the outermost surface (< 5 nm) is achieved when using a primary electron beam with an energy of < 1 kV.

In addition to low energy secondary electrons, backscattered electrons and X-rays are generated by primary electron bombardment. The intensity of backscattered electrons can be correlated to the atomic number of the element within the sampling volume. Hence, some qualitative elemental information can be obtained. The analysis of characteristic X-rays (EDX or EDS analysis) emitted from the sample gives more quantitative elemental information. Such X-ray analysis can be confined to analytical volumes as small as 1 cubic micron.

SEM, accompanied by X-ray analysis, is considered a relatively rapid, inexpensive, and basically non-destructive approach to surface analysis. It is often used to survey surface analytical problems before proceeding to techniques that are more surface-sensitive and specialized.

Recent News

On June 15, 2015, we took delivery of our new Hitachi SU3500 Variable Pressure Scanning Electron Microscope combined with an Oxford AZtec X-Max50 SDD energy dispersive detector. The SEM can be run in standard high vacuum mode and provides standard high resolution images and EDS micro analysis. The SU3500 can also operate at low pressures...

Congratulations to Ms. Thalia Standish, PhD candidate from the Department of Chemistry at Western University, winner of the 2015 Dr. N. Stewart McIntyre Award in Surface Science. Thalia’s research abstract was entitled “Galvanic Corrosion between Copper and Carbon Steel: An Investigation for Nuclear Waste Disposal Containers”. Thalia has used a variety of surface analysis techniques...

Prof. David Shoesmith, Department of Chemistry and Surface Science Western Director is the winner of this year’s H.H. Uhlig Award of the Corrosion Division of the Electrochemical Society. Dave will receive the award, and a reception in his honour will be held, at the Electrochemical Society fall meeting in Phoenix Arizona in October. This is...

It has been proposed that Canadian nuclear fuel waste be disposed of 500-1000 m deep in either granitic rock or sedimentary clay deposits. Within the multi-barrier system proposed, the fuel wastes would be sealed in a metallic container, which, in a sedimentary clay environment, could be a single thick-walled design fabricated from carbon steel. Raman...